Consequences

When clicking on the Updates and Upgrades page in Plesk, Plesk Web Installer prompts for a root password or does not open at all with one of the following error messages in a web-browser:

PLESK_INFO: The connection has timed out

PLESK_INFO: Can't connect to backend: No such file or directory

PLESK_INFO: This webpage is not available.

PLESK_INFO: ERR_CONNECTION_TIMED_OUT

When starting Plesk Installer in a command-line interface, the following message is shown:

CONFIG_TEXT: BUSY: Update operation was locked by another update process.

The following error message may appear in autoinstaller3.log (On Linux: /var/log/plesk/install/autoinstaller3.log, on Windows Server: C:\ParallelsInstaller\autoinstaller3.log:

CONFIG_TEXT: Error: Can't start build-in web-server.

Cause

Only one instance of Plesk Installer can be launched at a time.

Possible causes:

Previously started Plesk Web Installer process (Tools & Settings > Updates and Upgrades) is still running on the server. By design, if Plesk Web Installer was opened in a web-browser and then closed, its process will still be active in a background and then terminated automatically after 30 minutes of inactivity.

Previously started Plesk Installer process hanged for some reason and could not be terminated automatically.

Another Plesk administrator is using Plesk Installer.

Resolution

Terminate active Plesk Installer processes to start Plesk Installer.

Note: Before applying the solution below, make sure that other users on the Plesk server are not using Plesk Installer.

The described behavior in the article is not an issue in most cases. Usually, you can see such information message because another process is already running on the server, e.g. automatical updates installation procedure is running

However, issue each week is weird indeed...I suggest creating a ticket to Techincal Support in order to check all met issues together because it looks like that something is wrong on the server